A falling detection device (1), comprising a plurality of falling sensors (3) having movable contacts (35) disposed in metal cylindrical closed containers (101) and having contact parts provided at equal intervals and inertia bodies (36) stored in the closed containers, wherein the inertia bodies (36) press down the movable contacts (35) by their own weights to bring the contacts into contact with fixed contacts (31A) which are the inner peripheral surfaces of the closed containers, whereby the falling sensors can provide the same characteristics in all directions around the center axis of the closed containers.